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Performances of high density polyethylene (HDPE) plastic particles heated in a microwave chamber were detailed and the effects of chamber volume (100 ml, 150 ml, and 200 ml), feeding load (10 g, 20 g, and 30 g), and microwave power (500 W, 700 W, and 900 W) were investigated. The results showed that the temperatures of HDPE plastic particles increased to 220.2 °C, 288.3 °C and 352.3 °C during the sixty minutes for the 100 ml, 150 ml and 200 ml chamber volumes, and the average heating rates were 3.36 °C/min, 4.49 °C/min and 5.5 °C/min, respectively. The temperatures of HDPE plastic particles increased to 150.8 °C, 155.4 °C and 220.2 °C for the 10 g, 20 g and 30 g feeding loads, and the average heating rates were 2.22 °C/min, 2.29 °C/min and 3.36 °C/min, respectively. The temperatures of HDPE plastic particles increased to 161.5 °C, 192.8 °C and 220.2 °C for the 500 W, 700 W and 900 W microwave powers, and the average heating rates were 2.38 °C/min, 2.89 °C/min and 3.36 °C/min, respectively. Equations were proposed to estimate the temperatures, and the relative errors were mainly between −16.46% and 16.03%.

A fluidized bed system was demonstrated and the fluidization performances of silicon carbide in the fluidized bed system were experimentally studied as to facilitate the further application of microwave-assisted fluidized bed. The results show that the smaller silicon carbide particles (0.25–1 mm) have better fluidization performances than larger ones (1–1.5, 1.5–2, 2–2.5 and 2.5–3 mm) due to the fact that the smaller particles are nearly spherical whereas the larger particles are irregular in shape (long and branched), and larger particles tend to form channels in fluidization. Fluidization velocity is too high, large bubbles will be generated to affect the uniformity of fluidized particles. The loading of fluidized particles should match that of the fluidized bed, and too low loading amount wastes the space of the fluidized bed, while too high loading amount will also produce large bubbles. For the fluidized bed system developed in this study, the suggested fluidization parameters were: (a) silicon carbide particle size of 0.25–1 mm, (b) fluidization velocity of 0.47–-0.71 m/s, and (c) silicon carbide particle loading of 40–50 g.

Fluidization is an effective method to better help the transfer and conversion of fuel particles. In this study, intensification of the fluidization performances of polypropylene was experimentally investigated by using microwave absorbent. The fluidization performances of polypropylene (PP) were initially presented and the effects of microwave absorbent (SiC) particle size, mass ratio of SiC to PP, and fluidization velocity on the co-fluidization performances were studied and presented. The results showed that the PP load significantly increased the initial bed height whereas slightly increased the critical fluidization velocity and bed expansion ratio. Adding microwave absorbent (SiC) can effectively improve the fluidization performance of PP particles. The smaller SiC particles (0.25−1 mm) had better fluidization performances than the larger ones (1–1.5 mm and 1.5−2 mm). The mass ratio of silicon carbide to polypropylene decreased the critical fluidization velocity. Fluidization velocity significantly affected the co-fluidization performance. For the co-fluidization of polypropylene and silicon carbide in the designed fluidized bed, the recommended fluidization parameters were: (a) the particle size of silicon carbide of 0.25–1 mm, (b) the mass ratio of silicon carbide to polypropylene of 3:2, and (c) the fluidization velocity of 0.66 m/s.